Remove/install coolant lines - AR20.20-P-7440GQC

ENGINE 276.8 in MODEL 166, 251 

Fig 1: Identifying Coolant Lines Remove/Install Components - Shown On Model 251

Courtesy of MERCEDES-BENZ USA

Shown on model 251 

Fig 2: Identifying Coolant Lines Remove/Install Components - Shown On Model 251

Courtesy of MERCEDES-BENZ USA

	Risk of injury  caused by scraping or cutting body parts on sharp vehicle parts	Always wear protective gloves when working on or near sharp and non-deburred vehicle parts. Deburr repair panels.	AS00.00-Z-0017-01A
	Risk of injury  caused by fingers being jammed or pinched when removing, installing or aligning hoods, doors, trunk lid/rear-end door or sliding roof.	No parts of the body or limbs should be within the operating area when the components are moving.	AS00.00-Z-0011-01A
	Remove/install
1	Drain coolant	ENGINE 276.8 in MODEL 166	AR20.00-P-1142GQ
	Notes on coolant		AH20.00-N-2080-01A
		ENGINE 276.8 in MODEL 251	AR20.00-P-1142GZC
	Perform operation step 2 to 6 for removal of the left (2L) or right (2R) coolant return line
2	Detach left or right air filter housing		AR09.10-P-1150GQC
3	Detach charge air cooler at both charge air pipes and at throttle valve actuator and pull to the front	Only when removing left coolant return line (2L).
			AR09.41-P-6819GQC
4	Detach right (2R) or left (2L) oil line return line at connection for coolant hose (3)	The coolant hose connection (3) is located for model 166 on the left cylinder head.
5	Detach heat shields (4) or heat shields (8)	Bolt, turbocharger shield bracket to cylinder head	*BA09.40-P-1012-01W
		Bolt/nut for shield attachment	*BA09.40-P-1011-01W
6	Remove right (2R) or left (2L) coolant return line	Close off openings using a set of stop plugs.
		Bolt for coolant line attachment	*BA09.40-P-1010-01W
		Bolt, coolant feed line to crankcase	*BA09.40-P-1009-01W
		Bolt, coolant feed/return line to turbocharger	*BA09.40-P-1008-01W
		Record plug	Fig 3
	Perform operation step 7 to 9 for removal of the left (1L) or right (1R) coolant feed line
7	Detach left or right air filter housing		AR09.10-P-1150GQC
8	Remove windshield wiper system	ENGINE 276.8 in MODEL 251
			AR82.30-P-6400RT
9	Remove CAT on the left or right	ENGINE 276.8 in MODEL 251
			AR49.10-P-5500GQC
10	Detach heat shield (6) over crankshaft Hall sensor	Only for removal of the left coolant feed line
		Bolt/nut for shield attachment	*BA09.40-P-1011-01W
11	Detach heat shield (5) over knock sensor	Only for removal of the left coolant feed line
		Bolt/nut for shield attachment	*BA09.40-P-1011-01W
12	Remove heat shield over knock sensor	Only for removal of the left coolant feed line
13	Detach heat shield (7) over starter	Only for removal of the right coolant feed line
		Bolt/nut for shield attachment	*BA09.40-P-1011-01W
14	Remove right (1R) or left (1L) coolant feed line	Replace sealing ring. Use suitable stop plugs to seal the openings .
		Bolt, coolant feed/return line to turbocharger	*BA09.40-P-1008-01W
		Bolt, coolant feed line to crankcase	*BA09.40-P-1009-01W
		Bolt for coolant line attachment	*BA09.40-P-1010-01W
15	Install in the reverse order
15	Install in the reverse order
16	Check cooling system for leak tightness	ENGINE 276.8 in MODEL 166	AR20.00-P-1010GQ
		ENGINE 276.8 in MODEL 251	AR20.00-P-1010GZC
	Risk of accident  from vehicle starting off by itself when engine running. Risk of injury  (bruises and burns) resulting from working on the engine while it is being started or when it is running.	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
17	Carry out an engine test run, checking the engine for leak tightness and proper operation

Fig 3: Identifying Record Plug (129 589 00 91 00)

Courtesy of MERCEDES-BENZ USA